Fluidisation is a known principle. It is used to make the behaviour of a granular, powdery or like substance similar to that of a fluid. Fluidisation consists in injecting a low speed flow of gas into the particles of the substance, the flow of gas entrains the particle in a rising motion which is opposed by gravity, and this can be arranged to give the gas-particle mixture the behaviour of a fluid. The flow of gas is generally obtained by making the fluidising gas pass through a porous plate. Fluidisers are generally rigid and constitute the bottom of a fluidising tank, or if not actually constituting the bottom they are very securely fastened thereto. Further, current design for fluidising tank bottoms results in the members being difficult to disassemble, requiring a large amount of work to change the porous plate for example.
The aim of the present invention is to simplify the design of such fluidising members so that they may be rapidly changed should the need arise. Another aim of the invention is to provide means for mixing the fluidised substance by creating zones of differing degrees of fluidisation.